revert(3p/git): Revert merge of git upstream at v2.26.2 r/852

This causes cgit to serve error pages, which is undesirable.

This reverts commit 5229c9b232de5bfa959ad6ebbb4c8192ac513352, reversing
changes made to f2b211131f2347342dde63975b09cf603149f1a3.

1 files changed, 85 insertions, 204 deletions

diff --git a/third_party/git/builtin/name-rev.c b/third_party/git/builtin/name-rev.c
index a9dcd25e4647..c785fe16bade 100644
--- a/third_party/git/builtin/name-rev.c
+++ b/third_party/git/builtin/name-rev.c
@@ -6,25 +6,20 @@
 #include "tag.h"
 #include "refs.h"
 #include "parse-options.h"
-#include "prio-queue.h"
 #include "sha1-lookup.h"
 #include "commit-slab.h"
 
-/*
- * One day.  See the 'name a rev shortly after epoch' test in t6120 when
- * changing this value
- */
-#define CUTOFF_DATE_SLOP 86400
+#define CUTOFF_DATE_SLOP 86400 /* one day */
 
-struct rev_name {
-	char *tip_name;
+typedef struct rev_name {
+	const char *tip_name;
 	timestamp_t taggerdate;
 	int generation;
 	int distance;
 	int from_tag;
-};
+} rev_name;
 
-define_commit_slab(commit_rev_name, struct rev_name);
+define_commit_slab(commit_rev_name, struct rev_name *);
 
 static timestamp_t cutoff = TIME_MAX;
 static struct commit_rev_name rev_names;
@@ -32,16 +27,16 @@ static struct commit_rev_name rev_names;
 /* How many generations are maximally preferred over _one_ merge traversal? */
 #define MERGE_TRAVERSAL_WEIGHT 65535
 
-static int is_valid_rev_name(const struct rev_name *name)
+static struct rev_name *get_commit_rev_name(struct commit *commit)
 {
-	return name && (name->generation || name->tip_name);
+	struct rev_name **slot = commit_rev_name_peek(&rev_names, commit);
+
+	return slot ? *slot : NULL;
 }
 
-static struct rev_name *get_commit_rev_name(const struct commit *commit)
+static void set_commit_rev_name(struct commit *commit, struct rev_name *name)
 {
-	struct rev_name *name = commit_rev_name_peek(&rev_names, commit);
-
-	return is_valid_rev_name(name) ? name : NULL;
+	*commit_rev_name_at(&rev_names, commit) = name;
 }
 
 static int is_better_name(struct rev_name *name,
@@ -80,135 +75,68 @@ static int is_better_name(struct rev_name *name,
 	return 0;
 }
 
-static struct rev_name *create_or_update_name(struct commit *commit,
-					      timestamp_t taggerdate,
-					      int generation, int distance,
-					      int from_tag)
-{
-	struct rev_name *name = commit_rev_name_at(&rev_names, commit);
-
-	if (is_valid_rev_name(name)) {
-		if (!is_better_name(name, taggerdate, distance, from_tag))
-			return NULL;
-
-		/*
-		 * This string might still be shared with ancestors
-		 * (generation > 0).  We can release it here regardless,
-		 * because the new name that has just won will be better
-		 * for them as well, so name_rev() will replace these
-		 * stale pointers when it processes the parents.
-		 */
-		if (!name->generation)
-			free(name->tip_name);
-	}
-
-	name->taggerdate = taggerdate;
-	name->generation = generation;
-	name->distance = distance;
-	name->from_tag = from_tag;
-
-	return name;
-}
-
-static char *get_parent_name(const struct rev_name *name, int parent_number)
-{
-	struct strbuf sb = STRBUF_INIT;
-	size_t len;
-
-	strip_suffix(name->tip_name, "^0", &len);
-	if (name->generation > 0) {
-		strbuf_grow(&sb, len +
-			    1 + decimal_width(name->generation) +
-			    1 + decimal_width(parent_number));
-		strbuf_addf(&sb, "%.*s~%d^%d", (int)len, name->tip_name,
-			    name->generation, parent_number);
-	} else {
-		strbuf_grow(&sb, len +
-			    1 + decimal_width(parent_number));
-		strbuf_addf(&sb, "%.*s^%d", (int)len, name->tip_name,
-			    parent_number);
-	}
-	return strbuf_detach(&sb, NULL);
-}
-
-static void name_rev(struct commit *start_commit,
+static void name_rev(struct commit *commit,
 		const char *tip_name, timestamp_t taggerdate,
-		int from_tag, int deref)
+		int generation, int distance, int from_tag,
+		int deref)
 {
-	struct prio_queue queue;
-	struct commit *commit;
-	struct commit **parents_to_queue = NULL;
-	size_t parents_to_queue_nr, parents_to_queue_alloc = 0;
-	struct rev_name *start_name;
-
-	parse_commit(start_commit);
-	if (start_commit->date < cutoff)
-		return;
+	struct rev_name *name = get_commit_rev_name(commit);
+	struct commit_list *parents;
+	int parent_number = 1;
+	char *to_free = NULL;
 
-	start_name = create_or_update_name(start_commit, taggerdate, 0, 0,
-					   from_tag);
-	if (!start_name)
-		return;
-	if (deref)
-		start_name->tip_name = xstrfmt("%s^0", tip_name);
-	else
-		start_name->tip_name = xstrdup(tip_name);
+	parse_commit(commit);
 
-	memset(&queue, 0, sizeof(queue)); /* Use the prio_queue as LIFO */
-	prio_queue_put(&queue, start_commit);
-
-	while ((commit = prio_queue_get(&queue))) {
-		struct rev_name *name = get_commit_rev_name(commit);
-		struct commit_list *parents;
-		int parent_number = 1;
-
-		parents_to_queue_nr = 0;
+	if (commit->date < cutoff)
+		return;
 
-		for (parents = commit->parents;
-				parents;
-				parents = parents->next, parent_number++) {
-			struct commit *parent = parents->item;
-			struct rev_name *parent_name;
-			int generation, distance;
+	if (deref) {
+		tip_name = to_free = xstrfmt("%s^0", tip_name);
 
-			parse_commit(parent);
-			if (parent->date < cutoff)
-				continue;
+		if (generation)
+			die("generation: %d, but deref?", generation);
+	}
 
-			if (parent_number > 1) {
-				generation = 0;
-				distance = name->distance + MERGE_TRAVERSAL_WEIGHT;
-			} else {
-				generation = name->generation + 1;
-				distance = name->distance + 1;
-			}
+	if (name == NULL) {
+		name = xmalloc(sizeof(rev_name));
+		set_commit_rev_name(commit, name);
+		goto copy_data;
+	} else if (is_better_name(name, taggerdate, distance, from_tag)) {
+copy_data:
+		name->tip_name = tip_name;
+		name->taggerdate = taggerdate;
+		name->generation = generation;
+		name->distance = distance;
+		name->from_tag = from_tag;
+	} else {
+		free(to_free);
+		return;
+	}
 
-			parent_name = create_or_update_name(parent, taggerdate,
-							    generation,
-							    distance, from_tag);
-			if (parent_name) {
-				if (parent_number > 1)
-					parent_name->tip_name =
-						get_parent_name(name,
-								parent_number);
-				else
-					parent_name->tip_name = name->tip_name;
-				ALLOC_GROW(parents_to_queue,
-					   parents_to_queue_nr + 1,
-					   parents_to_queue_alloc);
-				parents_to_queue[parents_to_queue_nr] = parent;
-				parents_to_queue_nr++;
-			}
+	for (parents = commit->parents;
+			parents;
+			parents = parents->next, parent_number++) {
+		if (parent_number > 1) {
+			size_t len;
+			char *new_name;
+
+			strip_suffix(tip_name, "^0", &len);
+			if (generation > 0)
+				new_name = xstrfmt("%.*s~%d^%d", (int)len, tip_name,
+						   generation, parent_number);
+			else
+				new_name = xstrfmt("%.*s^%d", (int)len, tip_name,
+						   parent_number);
+
+			name_rev(parents->item, new_name, taggerdate, 0,
+				 distance + MERGE_TRAVERSAL_WEIGHT,
+				 from_tag, 0);
+		} else {
+			name_rev(parents->item, tip_name, taggerdate,
+				 generation + 1, distance + 1,
+				 from_tag, 0);
 		}
-
-		/* The first parent must come out first from the prio_queue */
-		while (parents_to_queue_nr)
-			prio_queue_put(&queue,
-				       parents_to_queue[--parents_to_queue_nr]);
 	}
-
-	clear_prio_queue(&queue);
-	free(parents_to_queue);
 }
 
 static int subpath_matches(const char *path, const char *filter)
@@ -229,10 +157,10 @@ static const char *name_ref_abbrev(const char *refname, int shorten_unambiguous)
 {
 	if (shorten_unambiguous)
 		refname = shorten_unambiguous_ref(refname, 0);
-	else if (skip_prefix(refname, "refs/heads/", &refname))
-		; /* refname already advanced */
-	else
-		skip_prefix(refname, "refs/", &refname);
+	else if (starts_with(refname, "refs/heads/"))
+		refname = refname + 11;
+	else if (starts_with(refname, "refs/"))
+		refname = refname + 5;
 	return refname;
 }
 
@@ -247,10 +175,6 @@ static struct tip_table {
 	struct tip_table_entry {
 		struct object_id oid;
 		const char *refname;
-		struct commit *commit;
-		timestamp_t taggerdate;
-		unsigned int from_tag:1;
-		unsigned int deref:1;
 	} *table;
 	int nr;
 	int alloc;
@@ -258,18 +182,13 @@ static struct tip_table {
 } tip_table;
 
 static void add_to_tip_table(const struct object_id *oid, const char *refname,
-			     int shorten_unambiguous, struct commit *commit,
-			     timestamp_t taggerdate, int from_tag, int deref)
+			     int shorten_unambiguous)
 {
 	refname = name_ref_abbrev(refname, shorten_unambiguous);
 
 	ALLOC_GROW(tip_table.table, tip_table.nr + 1, tip_table.alloc);
 	oidcpy(&tip_table.table[tip_table.nr].oid, oid);
 	tip_table.table[tip_table.nr].refname = xstrdup(refname);
-	tip_table.table[tip_table.nr].commit = commit;
-	tip_table.table[tip_table.nr].taggerdate = taggerdate;
-	tip_table.table[tip_table.nr].from_tag = from_tag;
-	tip_table.table[tip_table.nr].deref = deref;
 	tip_table.nr++;
 	tip_table.sorted = 0;
 }
@@ -280,30 +199,12 @@ static int tipcmp(const void *a_, const void *b_)
 	return oidcmp(&a->oid, &b->oid);
 }
 
-static int cmp_by_tag_and_age(const void *a_, const void *b_)
-{
-	const struct tip_table_entry *a = a_, *b = b_;
-	int cmp;
-
-	/* Prefer tags. */
-	cmp = b->from_tag - a->from_tag;
-	if (cmp)
-		return cmp;
-
-	/* Older is better. */
-	if (a->taggerdate < b->taggerdate)
-		return -1;
-	return a->taggerdate != b->taggerdate;
-}
-
 static int name_ref(const char *path, const struct object_id *oid, int flags, void *cb_data)
 {
 	struct object *o = parse_object(the_repository, oid);
 	struct name_ref_data *data = cb_data;
 	int can_abbreviate_output = data->tags_only && data->name_only;
 	int deref = 0;
-	int from_tag = 0;
-	struct commit *commit = NULL;
 	timestamp_t taggerdate = TIME_MAX;
 
 	if (data->tags_only && !starts_with(path, "refs/tags/"))
@@ -352,6 +253,8 @@ static int name_ref(const char *path, const struct object_id *oid, int flags, vo
 			return 0;
 	}
 
+	add_to_tip_table(oid, path, can_abbreviate_output);
+
 	while (o && o->type == OBJ_TAG) {
 		struct tag *t = (struct tag *) o;
 		if (!t->tagged)
@@ -361,33 +264,16 @@ static int name_ref(const char *path, const struct object_id *oid, int flags, vo
 		taggerdate = t->date;
 	}
 	if (o && o->type == OBJ_COMMIT) {
-		commit = (struct commit *)o;
-		from_tag = starts_with(path, "refs/tags/");
-		if (taggerdate == TIME_MAX)
-			taggerdate = commit->date;
-	}
+		struct commit *commit = (struct commit *)o;
+		int from_tag = starts_with(path, "refs/tags/");
 
-	add_to_tip_table(oid, path, can_abbreviate_output, commit, taggerdate,
+		if (taggerdate == TIME_MAX)
+			taggerdate = ((struct commit *)o)->date;
+		path = name_ref_abbrev(path, can_abbreviate_output);
+		name_rev(commit, xstrdup(path), taggerdate, 0, 0,
 			 from_tag, deref);
-	return 0;
-}
-
-static void name_tips(void)
-{
-	int i;
-
-	/*
-	 * Try to set better names first, so that worse ones spread
-	 * less.
-	 */
-	QSORT(tip_table.table, tip_table.nr, cmp_by_tag_and_age);
-	for (i = 0; i < tip_table.nr; i++) {
-		struct tip_table_entry *e = &tip_table.table[i];
-		if (e->commit) {
-			name_rev(e->commit, e->refname, e->taggerdate,
-				 e->from_tag, e->deref);
-		}
 	}
+	return 0;
 }
 
 static const unsigned char *nth_tip_table_ent(size_t ix, void *table_)
@@ -419,11 +305,11 @@ static const char *get_exact_ref_match(const struct object *o)
 static const char *get_rev_name(const struct object *o, struct strbuf *buf)
 {
 	struct rev_name *n;
-	const struct commit *c;
+	struct commit *c;
 
 	if (o->type != OBJ_COMMIT)
 		return get_exact_ref_match(o);
-	c = (const struct commit *) o;
+	c = (struct commit *) o;
 	n = get_commit_rev_name(c);
 	if (!n)
 		return NULL;
@@ -431,10 +317,11 @@ static const char *get_rev_name(const struct object *o, struct strbuf *buf)
 	if (!n->generation)
 		return n->tip_name;
 	else {
+		int len = strlen(n->tip_name);
+		if (len > 2 && !strcmp(n->tip_name + len - 2, "^0"))
+			len -= 2;
 		strbuf_reset(buf);
-		strbuf_addstr(buf, n->tip_name);
-		strbuf_strip_suffix(buf, "^0");
-		strbuf_addf(buf, "~%d", n->generation);
+		strbuf_addf(buf, "%.*s~%d", len, n->tip_name, n->generation);
 		return buf->buf;
 	}
 }
@@ -594,15 +481,9 @@ int cmd_name_rev(int argc, const char **argv, const char *prefix)
 		add_object_array(object, *argv, &revs);
 	}
 
-	if (cutoff) {
-		/* check for undeflow */
-		if (cutoff > TIME_MIN + CUTOFF_DATE_SLOP)
-			cutoff = cutoff - CUTOFF_DATE_SLOP;
-		else
-			cutoff = TIME_MIN;
-	}
+	if (cutoff)
+		cutoff = cutoff - CUTOFF_DATE_SLOP;
 	for_each_ref(name_ref, &data);
-	name_tips();
 
 	if (transform_stdin) {
 		char buffer[2048];